Learn more about Ophthalmic diagnosis, care, and treatments with this comprehensive encyclopedia.
Branch retinal artery occlusionThis type of occlusion occurs when a small branch retinal artery becomes blocked or clogged. Within the arteries of the retina, occlusions most often occur due to a clot that originates from another vessel in the body and finally lodges in a small branch retinal artery.
When an occlusion occurs in a branch retinal artery, a small area of cells in the retina is deprived of oxygen. In occlusions that occur in branch retinal arteries, the affected cells most certainly die. Retinal artery occlusions occur suddenly, causing immediate and noticeable decreased vision in one eye. The vision loss is usually permanent, but often not as drastic as what occurs when the central retinal artery becomes blocked.
There are ways to lessen the chance that a future occlusion will occur. Most people who have an occlusion in an artery of the retina have high blood pressure, high cholesterol, or some form of vessel disease. When proper steps are taken to control blood pressure, cholesterol, and blood sugar, the occurrence of another occlusion is much less likely.
Best's DiseaseBest’s disease is a disease categorized as a hereditary chorioretinal dystrophy. It is a rare, genetic disease that is characterized by a large, yellow protein that forms under the retinal pigment epithelium (RPE) in the area of the macula.
Inherited eye conditions usually present themselves early in life. Best’s disease is usually diagnosed during childhood, but the onset and severity of symptoms varies. Often, the large, fluid-filled drusen (resembling an egg yolk) beneath the RPE does not affect vision. Eventually, though, this drusen will rupture, and fluid and protein molecules will spread beneath the retina. Central vision will become worse over time, but not to the point of blindness. Best’s disease cannot be cured, but it is possible to adapt quite well to limited vision. Peripheral vision will not be affected, and one eye will often retain good central vision.
Only one copy of the gene responsible for Best’s disease is needed to cause its expression. Therefore, if one parent has the condition, there is a 50/50 chance that a child will inherit the disease. A similar form of Best’s disease that occurs later in life, and whose pattern of inheritance is unknown, is Adult Vitelliform Macular Degeneration.
Basal Laminar DrusenBasal laminar drusen are small, round, uniformly sized, yellow drusen (accumulations of extracellular material that build up in the eye) scattered in clusters between the pigment epithelial layer and the bottom-most Bruch’s membrane of the retina. Imaging technologies such as fluorescein angiography (FA) depict basal laminar drusen as appearing in a “starry sky” pattern.
Basal laminar drusen often are seen in conjunction with a pseudovitelliform detachment of the macula. Alone, these kind of drusen have little or no effect on vision.